Firing system for steam-boilers



G. A. BRYAN.

FIRING SYSTEM FOR STEAM BOILERS.

APPLICATION FILED MAY29. I918.

Patented Sept. 23, 1919.

INVENTOR.

- I TNESS:

A TTORN E Y5 GEORGE A. BRYAN, OF ALBUQUERQUE, NEW MEXICO.

FIRING SYSTEM FOR STEAMBOILERS.

Specification of Letters Patent.

Patented Sept. 23, 1919.

Application filed May 29, 1918. Serial No. 237,196.

To all whom it may concern:

Be it known that I, Gnoncr. A. BRYAN, a citizen of the United States,residing at Albuquerque, in the county of Bernalillo and State of NewMexico, have invented certain new and useful Improvements in FiringSystems for Steam-Boilers, of which the following is a full, clear, andexact description.

This invention relates to firing systems for steam generators adaptedparticularly for steam propelled vehicles and in which liquid fuel isutilized. The object of the invention is to provide an automatic systemfor maintaining and controlling the pressure generated, by igniting andextinguishing the burner as may be required, and in which steam or airused under pressure for vaporizing the fuel at the burner, is maintainedat a uniform pressure regardless of the main pressure in the boiler. Incarrying out the invention I use in connection with the burner asparking device and a fuel spraying nozzle with means whereby the fluidsupplied under pressure to the nozzle will at the same time serve toactuate an automatic electric switch to supply the ignition spark. Ialso use a control valve which when the boiler pressure reaches themaximum, will simultaneously cut off the fluid pressure to the burnerand restore the automatic switch to position to be again actuated whenthe burner is to be ignited. There is also used a pressure regulator formaintaining a uniform pressure of the steam supplied to the burner forvaporizing purposes, regardless of the ressure in the boiler and asource of uni orm air pressure for vaporizing the fuel in starting.These features will all be described in detail hereinafter withreference to the accompanying'drawing, in which the figure is aconventional representation of the entire system comprehended by myinvention.

Referring. to the drawing, 1 indicates a portion of a steam boiler, ofwhich the lower part 2 is the fire chamber. Attached to the front wallof the fire chamber is a burner 3 of any approved form but comprising afuel nozzle 4, and a spraying nozzle 5 from which a blast of air orsteam is delivered across the outlet of the fuel nozzle 4: in order todraw the fuel from the latter and spray it into the firing chamber 2.The rear end of the burner is provided with air openings 6 affording thenecessary oxygen forcombustion. The mixture of sprayed fuel and air issubject to ignition by a spark plug 7 which projects into the mixingchamber of the burner. 8 is a cylinder containing a piston 9 normallyheld at the lower end of the cyllnder by a spring 10. A pipe 11 leadsfrom nozzle 5 of the burner to a port in the side wall of cylinder 8 toestablish communicatlon between said cylinder and the nozzle. The portin the cylinder is normally closed by the plston 9 while in itslowermost position. The piston rod 12 passes through the upper end ofthe cylinder and engages a pitoted contact lever 13, the free end ofwhich rests upon a segment consisting of two termlnal insulatingportions 14 and 15 and an intermediate conducting portion 16, thereciprocation of the piston 9 causing the contact arm to travel from oneinsulating block to the other and in the transit making temporaryelectrical connection with the conducting portion 16. 17 is an inductioncoil having the usual primary and secondary windings and provided with avibrator of ordinary construction located in the primary circuit, whichalso includes a battery 18. a switch 19, and whose terminals arerespectively connected to a contact shoe on the end of arm 13 and to theconducting segment 16. The terminals of the secondary winding of theinduction coil are respectively connected with one of the terminals ofthe spark plug 7 and with the frame of the burner, as shown, the otherterminal of the spark plug being understood as grounded upon the frameof the burner so that high tension currents induced in the secondarywinding of the induction coil will produce corresponding sparks at theterminals of the spark plug for igniting the mixture in the burner. At20 is shown in section what I term a main controlling valve comprising aframe within which is fixed a diaphragm 21, to which is attached a valvestem 22 leading to a valve 23 seated in an inlet port 2 1 in the bottomof the structure. Beneath the diaphragm is located a heavy spring 25,the tension of which is adjustable by means of a nut 26. The port 24:opens into a chamber 27, from which leads a pipe 28 to the bottom ofcylinder 8. The pressure of the spring 25 against the under side of thediaphragm 21 is offset by steam pressure on the other side of saiddiaphragm supplied through a pipe 29 directly from the boiler 1. It willtherefore be seen that by adjusting the tension of spring 25 to a givenvalue the valve 23 will be held open by the spring until that value isslightly exceeded by the steam pressure above the diaphragm, at whichtime the valve 23 will close. At 30 is shown a device similar to thatjust described but which I term a steam pressure regulator. This devicecomprises a frame within which is fixed a diaphragm 31 to which isattached a valve rod 32 leading to a valve 33 which controls a port 34in the lower end of the device. Beneath the diaphragm is a spring 35considerably lighter than the spring 25 in the main valve and whosetension can be adjusted by means of the nut 36 through which the valvestem freely passes. Port 34 admits steam from pipe 37 into the chamber38, from which the steam is free to pass out through the pipe 39. Frompipe 39 a branch pipe 40 leads to the chamber above diaphragm 31, whileanother branch leads by pipes 41 and 42 to port 24 in the lower end ofthe main control valve 20. 43 is a four-way valve to which leads a steampipe 44 direct from the boiler 1 and an air pipe 45 from an air tank 46.From this four-way valve leads the steam pipe 37 which connects with theport 34 in the steam pressure regulator and the air pipe 47 whichconnects with the-pipe 42 leading to the port 24 in the lower end of themain control valve, 48 is a float chamber to Which gasolene, kerosene orother suitable liquid fuel is supplied through the pipe 49 leadin froman elevated tank or a supply of fiiel under pressure. From this floatchamber a pipe 50 connects with the fuel nozzle 4 within the burner, itbeing understood that the float maintains the level of the liquid in thechamber on a line with the outlet of the nozzle.

The operation of the system is as follows:

In order to start the burner into operation the hand switch 19 in theprimary circuit is first closed, then the four-way valve 43 is turned soas to connect the air supply from tank 46 with the ipe 47. From thispipe the pressure leads t rough pipe 42 into chamber 27 of the maincontrol valve. From this chamber the air passes freely through pipe 28into the lower end of the cylinder 8, where it forces the piston 9upward and uncovers the port leading to pipe 11; from ipe 11 air escapesthrough the nozzle 5 1nto the burner, thereby drawing fuel from thenozzle 4 and spraying it, together with air from the ports 6, into thefire chamber 2.

When the piston 9 rises the contact arm 13 is carried onto theconducting segment 16 and closes the primary circuit of the inductioncoil, which causes an interrupted current to flow in the primary, due tothe action of the vibrator, and a corresponding secondary vibratorycurrent to bridge the contacts at the spark plug, creating a series ofsparks which lgnites the mixture. The sparking continues at the plug toinsure the ignition of the mixture while the contact arm 13 traversesthe conducting segment 16, and this period is determined by the rapidityof movement of the piston 9, which, during the first part of its strokeis rapid, but upon the release of the pressure throu h the pipe 11, isdelayed slightly until finally the piston is at the end of its stroke,when the contact arm has passed on to the insulating block 15. Thepiston 9 remains in its upper position because of the fact that theoutlet from the cylinder 8 through pipe 11 is more restricted than theinlet thereto through the pipe 28, thus insuring an accumulation ofpressure in the cylinder, which holds the pistonin its elevatedposition. This condition continues until the pressure in the boiler hasbeen raised sutficiently to enable it to be used for atomizing at theburner, Whereupon, in order to conserve air pressure, the four-way valve43 is turned to cut off the air and connect pipe 44 with pipe 37. Steamat boiler pressure will then flow through pipe 37 to the chamber 38 inthe steam pressure regulator, when it will pass out through the pi e 39to the u per side of diaphragm 31 an to the cham er 27 in the maincontrol valve. From the latter chamber the steam will lead through pipe28 to the cylinder 8 and thence to the burner, where it will serve toatomize the fuel in the same manner as previously done by the air. Thisis the normal operatin condition of the system. Should the boilerpressure rise to an excessive oint where the pressure direct from theoiler above diaphragm 21 will close the valve 23, the pressure at theburner will be out 01f and the flame extinguished. At the same timepiston 9 will drop to its lowest position, returning the arm 13 to theupper end of its stroke. This condition will continue until the pressurefalls so that spring 25 in'the main control valve again opens valve 23,whereupon piston 9' rises to again admit pressure to the burner and tosupply the igniting spark, whereupon steam is again generated in theboiler. In this way the main control valve not only serves as a safetyvalve but conserves fuel by avoiding a blow off. The pressure necessaryto supply the atomizing blast at the burner is considerably less thanmain boiler pressure and it is desirable that this burner pressureshould be maintained uniform under all conditions. This is the functionof the steam pressure regulator 30. It will be seen that the boilerpressure which enters the lower chamber 38 in this device has accessalso to the chamber on the upper side of diaphragm 31, and by settingthe tension of spring 35 so that it will yield to the pressure desiredat the burner the valve 33 will close orthrottle the ort 34 sufficientlyto maintain the desired pressure of steam in that part of the systembeyond the regulator. The air pressure used for starting the system isof substantially the same pressure as the steam which is used underrunning conditions and this air pressure may be maintained in anydesired and well known manner, as for instance by a pump which eitherstarts and stops automatically or which runs continuously with aprovision for escape of air above the required pressure. It is of courseevident that the system can be operated upon the air alone but foreconomic reasons it is desirable to use the steam for atomizing purposeswhenever it is available.

I claim:

1. The combination of an atomizing fuel burner, a source of fluidpressure and an ignition device connected therewith, an electric switchcontrolling said ignition device and means whereby the fluid pressureflowing to the burner will temporarily close the switch and then holdthe switch open as long as the pressure flows to the burner.

2. The combination of a boiler, an atomizing fuel burner therefor, asource of fluid pressure, an ignition device connected with the burner,an automatic controlling valve and a fluid pressure actuated switch,said controlling valve being subject to fluid pressure from the boilerand varying the flow of fluid pressure to the switch and burner.

3. The combination of a boiler, a fuel burner therefor comprising anatomizer, a duct for fluid pressure leading to the atomizer, a maincontrolling valve subject to boiler pressure and controlling the flow offluid in said duct. two sources of fluid pressure, one of which isconstant and the other boiler pressure, an automatic controlling valvefor maintaining the boiler pressure at any desired uniform value, andmeans for admitting either of said two sources of pressure to said ductat will.

4. The combination of a boiler, a fuel burner therefor, comprising anatomizer, a duct for fluid pressure leading to the atomizer, a maincontrolling valve subject to boiler pressure and controlling the flow offluid in said duct, two sources of fluid pressure, one of which isconstant and the other boiler pressure, an automatic controlling valvefor maintaining the boiler pressure at any desired uniform value, meansfor admitting either of said two sources of pressure to said duct atwill, an electric igniter associated with said burner, and means forrendering the same active upon the passage of pressure in said duct.

5. The combination of an atomizing burner, a duct for fluid pressureleading thereto, an electric igniter associated therewith, a switchcontrolling the igniter circuit and comprising a reciprocating contactadapted to move from one open circuit position to another, and having anintermediate fixed contact with which the reciprocating contact engagesin its excursions, and a piston connected with the reciprocatin contact,and subjected to the fluid pressure 1n said duct.

6. The combination with a boiler of an atomizing fuel burner for heatingsaid boiler, means for conducting pressure from said boiler to saidburner, an ignition device for said burner, an electric switchcontrolling said ignition device, and means whereby this pressureflowing from said boiler to the burner will control said switch.

7. In a firing system for steam boilers, the combination with a burner,of means for supplying pressure from said boiler to the burner foratomizing purposes, an ignition device for said burner, an electricswitch controlling said ignition device, means whereby the pressureflowing from said boiler to the burner will control said switch, andmeans for automatically cutting off said pressure supply when the boilerpressure reaches a predetermined maximum.

8. The combination with an atomizing fuel burner, of a source of fluidpressure and an ignition device connected therewith, an electric switchcontrolling said ignition device, and means whereby fluid pressureflowing to the burner will close the switch.

In witness whereof I subscribe my signature.

GEORGE A. BRYAN.

